Need help with Rigify in Blender v2.83 not working
This error happens when you have moved &quot;spine.004&quot;. That's the 1st bone of the neck (counting from the bottom). This bone is &quot;loose&quot; and can be moved around. But, to generate the rig it must stay exactly on the chest spine &quot;spine.003&quot;.
You can move it back with the help of the 3D Cursor. Move the cursor to the spine's bone (spine.003, the big one). In Edit mode, press SHIFT + S, choose Cursor to Selected. Then select spine.004, press SHIFT + S, and choose Selection to Cursor. That's it.